Do bigger magnets automatically mean better?

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  • ZLTFUL
    ZLTFUL Posts: 5,640
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    mhardy6647 wrote: »
    The classic Altec Duplexes employ large and heavy (i.e, powerful) AlNiCo magnets for both the woofer & treble drivers. The high magnetic field and high flux density of these drivers is used to afford high sensitivity as well as high linearity. Sensitivity has rather fallen out of favor as a design criterion for loudspeakers, since watts are dirt cheap any more. :(

    The Altec woofers (like their contemporary drivers from JBL) were low-excursion drivers with huge (3 to 4 inch) but shallow voice coils -- very different than the current fashion in woofer design.

    2efqzn6smrlm.png

    eh511se0qo7q.png

    The treble (compression) drivers likewise used large diameter VCs and truly massive AlNiCo magnets. The JBL 2441 treble drivers I am currently using weigh about 25 lbs
    each. Not all of that's magnet, of course, but the magnets in 'em are pretty beefy.

    hed3gjyk5fuc.png


    39958549212_fab98689d5_h.jpgDSC_0457 (3) by Mark Hardy, on Flickr
    JBL 275 on the left; 2441 on the right, 2A3 direct-heated power triode :) for scale.

    Nerdy aside: "Gauss" as a unit of magnetic flux density has been superceded in the SI system with units of "Tesla" (T). One Gauss equals 1×10−4 Tesla (100 μT), so 1 Tesla = 10,000 Gauss.

    z3v6s61hszwm.png


    You just like to keep rubbing those JBLs in my nose don't you? :'(:D Really wish you coulda figured out a way short of dynamite to remove the stock horns.

    "Some people find it easier to be conceited rather than correct."

    "Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip
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  • mhardy6647
    mhardy6647 Posts: 33,030
    edited September 2018
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    :( Yeah, huh?

    Amusingly enough -- I asked again over at hifihaven & got a couple of good suggestions (brass putty knife being one, differential cooling - or heating - being another). I will tackle 'em one of these days with the some empathetic help from one of the local gurus. This summer was way more complicated than expected, given Mrs. H's eye problems (and travel) :(

    http://www.hifihaven.org/index.php?threads/so-i-have-an-interesting-problem-challenge-opportunity-a-stuck-horn.3930/
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  • ZLTFUL
    ZLTFUL Posts: 5,640
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    I'm just busting your chops. Would have liked to do a build with vintage compression drivers with the 15" HH Scott woofers (AlNiCo oddly enough) I ended up with for $50.
    "Some people find it easier to be conceited rather than correct."

    "Unwad those panties and have a good time man. We're all here to help each other, no matter how it might appear." DSkip
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  • mhardy6647
    mhardy6647 Posts: 33,030
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    I do indeed feel bad that "we" weren't able to pull that off. Maybe next year...

    Either way, I'd still like to separate the drivers & horns for my own nefarious purposes as well, you know? :)

    http://www.hifihaven.org/index.php?threads/ok-youse-guyses-i-am-a-sucka-for-cheap-horns.3682/
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  • motorstereo
    motorstereo Posts: 2,049
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    Jeez Doc.......3,000+ on that site, 18,000+ here and over 50,000 on ak!!!! How do you find time to even sit down and eat dinner lol
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  • treitz3
    treitz3 Posts: 18,316
    edited September 2018
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    You should see his post count on **** sites...

    (Rhymes with "corn")

    Tom
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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  • EndersShadow
    EndersShadow Posts: 17,528
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    motorstereo wrote: »
    Jeez Doc.......3,000+ on that site, 18,000+ here and over 50,000 on ak!!!! How do you find time to even sit down and eat dinner lol

    I think @mhardy6647 is really a robot and has us all fooled!
    "....not everything that can be counted counts, and not everything that counts can be counted." William Bruce Cameron, Informal Sociology: A Casual Introduction to Sociological Thinking (1963)
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  • mhardy6647
    mhardy6647 Posts: 33,030
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    ey7lbo8fbeb0.png

    selfie.
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  • pitdogg2
    pitdogg2 Posts: 24,559
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    mhardy6647 wrote: »
    ey7lbo8fbeb0.png

    selfie.

    Dang you're OLD lookie at all those wrinkles.
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  • mhardy6647
    mhardy6647 Posts: 33,030
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    ... but I'm well preserved.

    Oh, man... I crack myself up sometimes...
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  • mhardy6647
    mhardy6647 Posts: 33,030
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    motorstereo wrote: »
    Jeez Doc.......3,000+ on that site, 18,000+ here and over 50,000 on ak!!!! How do you find time to even sit down and eat dinner lol

    You skipped audioasylum.

    :p
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  • pitdogg2
    pitdogg2 Posts: 24,559
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    mhardy6647 wrote: »
    ... but I'm well preserved.

    Oh, man... I crack myself up sometimes...

    And lubed it seems lol
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